HERPES, an inflammation of the true skin, attended with the formation of isdlated or grouped vesicles of various sizes upon a reddened base. They contain a clear fluid, and either rupture or dry up. Two well-marked varieties of herpes are frequently met with. (a) In herpes labialis et nasalis the eruption occurs about the lips and nose. It is seen in cases of certain acute febrile ail ments, such as fevers, inflammation of the lungs or even in a severe cold. It soon passes off. (b) In herpes zoster, zone or "shingles" the eruption occurs in the course of one or more cutaneous nerves, often on one side of the trunk, but it may be on the face, limbs or other parts. It may occur at any age, but is more frequent in elderly people. The appearance of the erup tion is usually preceded by severe, stinging, neuralgic pains, and, not only during the continuance of the herpetic spots, but long after they have disappeared, these pains may continue. The disease seldom recurs. The most that can be done for its relief is to protect the parts with cotton wool or some dusting powder, while the pain may be allayed by aspirin or bromide of potassium. Quinine internally is often of service. Though the lesions are identical in appearance the two types differ in causation. Herpes labialis is due to a filter-passing virus which is inoculable into the rabbit's cornea; herpes zoster is associated with, and probably dependent upon, changes in the large cells of the posterior root ganglia (see SPINAL CORD) supplying the part affected.